Scientists Craft Working Chromosome for Yeast

By Robert Lee Hotz

In a stride toward creating artificial life, scientists announced Thursday that they crafted a working chromosome for yeast, a humble but complex organism long considered a workhorse of biotechnology in products from beer to biofuels and medicines.

Scientists and students led by geneticist Jef Boeke at New York University Langone Medical Center scrambled the DNA of yeast to alter the smallest of its 16 chromosomes with thousands of changes.

The experimental cells they created appeared to grow and behave normally, they reported Thursday in Science.

“It is an important milestone,” said synthetic biologist Christopher Voigt at the Massachusetts Institute of Technology, who wasn’t part of the research team. “Now you can design whatever chromosome you want and can be able to get it to work.”

For decades, researchers have been altering DNA a bit at a time to produce genetically engineered plants, insects and animals.

Genomics pioneer Craig Venter made headlines in 2010 by creating an experimental bacteria controlled by man-made genetic instructions. In a $40 million demonstration project, they altered a species of bacteria by replacing its genome with one they wrote themselves, signing their names in the chemical letters of its genetic code.

Several independent experts said that the new effort is a significant advance over that feat because yeast cells are a more complex life form that share basic cell biology with plants, animals and people. The genetic alterations also were more sweeping.

“If you look at the number of changes they made, it is significant—orders of magnitude more changes than anyone has made,” said synthetic biology pioneer Drew Endy at Stanford University, who wasn’t part of the effort. “What is really cool is that the resulting chromosome works just as well as the natural one.”

By showing how to make broad design changes in a key component of the basic machinery of life, the scientists offered a technique that potentially could be used to customize all sorts of creatures.

“We can control it very carefully,” said Dr. Boeke. “There are many applications of this technique to improving yeast for biotechnology as well as for understanding how cells work.”